Mica flake classifying device and method



May l0, 1955 M. D. HEYMAN MICA FLAKE CLASSIFYING DEVICE AND METHOD Filed Nov. 24, 1951 IN V EN TOR. M0555 HE www N lir 'DI United States 2,798,032 Patented May 10, 1955 tice MICA FLAKE CLASSIFYING DEVICE AND METHOD Moses D. Heyman, Woodmere, N. Y., assignor t Integrated Mica Corp., Woodmere, N. Y., a corporation of New York Application November 24, 1951, Serial No. 257,999

9 Claims. (Cl. 209-17) This invention relates to a device for selecting from a How of liquid-borne mica Hakes, those Hakes that, because of their relative thinness, are best adapted to be incorporated in a sheet of integrated mica. In the sense that the present device serves to pass Hakes that are classified as of required thinness and reject Hakes that are thicker than a required minimum, the same may be termed a classifier. This application is a continuationin-part of my pending application entitled Means and Method for Producing a Continuous Sheet of Integrated Mica, Ser. No. 201,020, filed December l5, 1950 which became Patent No. 2,659,412 on November 17, 1953.

Said application discloses disintegrating means for reducing pieces of mica into Hne splittings or Hakes while the same are immersed in a liquid medium. While the disintegrating means has substantial efficiency, the Hakes flowing therefrom in the liquid medium vary in thickness. Some of these Hakes are oversize and, if incorporated in a sheet of integrated mica, would impair the uniforrnity desired throughout such a sheet. Large surface area or size of the Hakes is not too material as the same does not impair sheet uniformity to a material degree, but thickness greater than a required minimum of, for instance, four microns, will result in material reduction in sheet uniformity as regards sheet thickness, electrical properties, strength, etc. Moreover,y the cohesive forces that cause the Hakes to form an integrated sheet, vary inversely as the square of the thickness of the Hakes. Consequently, the thinner the Hakes the better will ne the quality and strength of the integrated sheet formed therefrom.

It is to be understood that the present device is primarily intended to separate mica Hakes into an acceptable thin class and a rejected thick class without too much regard to the surface sizes of the Hakes. Incidental to the operation, however, the present classifier separates excessively large Hakes from the acceptable class to further improve the quality of the sheet that is formed.

Flotation alone, as disclosed in my Pat. No. 2,490,129, has the primary drawback of a large proportion of thin Hakes being pulled down in the liquid by theV thicker Hakes and, thus, removed from the How. Also, in simple flotation, Hakes that are thin enough but of excessively large surface area, will have such high buoyancy that the same will carry on its upper surfaces many Hakes that are too thick to, thereby, introduce such undesired Hakes into the How.

The present classifier employs the principle that objects in a liquid medium, if of greater specic gravity than said medium, have inertia causing them to remain inert in the medium. Mica has a specific gravity of 2.8 and all Hakes, both thick and thin, will settle in a liquid medium such as Water, methyl alcohol, carbon tetrachloride, aromatic solvents such as toluene, xylene, etc., or other suitable evaporative liquid media, and will remain inert therein. However, the thicker Hakes will settle downward more rapidly than will the thinner Hakes and will have greater inertia or resistance to flotation when the liquid in which the Hakes are immersed Vis stirred or agitated. The thinner the Hakes, the more rapid is their movement toward the surface of the liquid. While some excessively large thin Hakes may weigh as much as smaller thicker Hakes, they have high buoyancy by reason of their large surface area and will Hoat upwardly, whereas the thicker Hakes, lacking such buoyancy, will tend to remain at the bottom.

Accordingly, it is an object of the present invention to provide a mica Hake classifying device for removing from a How of liquid-borne mica Hakes or splittings, such Hakes, that by reason of their greater inertia, are thicker than a required minimum, so that the Hakes remaining in the How assemble to form an integrated sheet of desired properties.

Another object of the invention is to provide a classifying device, as above, in which the flow of liquid-borne Hakes is subjected to regular and repeated upward and downward displacement to urge the thinner and more buoyant Hakes progressively upward in the How.

A further object of the invention is to provide a classifying device of the character indicated in which the abovementioned up and down displacement takes place in a reciprocating receptacle that receives the How and in which the Hakes are also urged forwardly toward separate outlets for the thinner and the thicker Hakes.

A still further object of the invention is to provide mica Hake classifying means in which Hakes' that are floated upwardly are intercepted against resettling among the thicker Hakes and in which buoyant Hakes of unduly large size are intercepted and prevented from rising in the liquid medium.

A still further object of the invention is to provide a novel method for separating thin from relatively thicker Hakes or splittings of mica in a liquid How by pulsating the liquid to allow the thinner Hakes to progressively rise in the How and, thereby, become separated from the thicker and less buoyant Hakes.

The invention further comprises novel details and novel combinations and arrangement of parts hereinafter more fully described and illustrated in the accompanying drawing.

The foregoing objects of the invention and others that will become apparent in the course of the following description are realized in the preferred embodiment on which said description is based. It is to be understood, however, that the illustrated form of the invention is to be considered as by way of example only.

In the drawing:

Fig. 1 is a vertical sectional View of a mica flake classifying device according to the present invention.

Fig. 2 is an end elevational View as seen from the right of Fig. l and drawn to a reduced scale.

Fig. 3 is a fragmentary sectional view as taken on the line 3--3 of Fig. l and drawn to the scale of Fig. 2.

The illustrated classifier comprises, generally, a fixed support S, screen means 6 fixedly carried by said support and provided with a screen 7 across the bottom thereof, a receptacle 8 within which screen means 6 is positioned, an inlet 9 to said receptacle for a How of liquid-borne mica Hakes, an outlet 1G from the receptacle for part of said How, an outlet 11 for How passing from the receptacle through the screen means 6, means 12, carried by support 5 and connected to receptacle 8, to reciprocate the latter, and means 13, also carried by the support, for guiding the receptacle during reciprocation thereof.

The support S comprises a suitable base 14 and preferably upstanding frames 15 that fixedly mount screen means 6 in spaced relation to and above the base.

Screen means 6 is shown as a rectangular vertically disposed tube 16 that has a sloping lower end across which is disposed a sloping screen 7. In order that said screen may be readily replaced should different mesh sizes be desired, the same is mounted in a frame 17 and said frame separably engaged with a ledge 18 provided around the bottom of tube 16. ln practice, a gasket 19 is interposed between frame 17 and ledge 18. Screen means 6 is so disposed in relation to the How of liquid and flakes that said How can enter tube 16 only in an upward direction through screen 7. An exit opening 20 is provided in the wall of tube 16 that is opposite the highest edge of the sloping screen. As will be seen from Fig. l, the lowest point of said opening is somewhat above the highest edge of the screen.

Receptacle 8 is larger in its horizontal rectangular form than tube lo and surrounds said tu `e with ample clearance for How in the space 21 between tube 16 and tubular walls 22 of the receptacle. The bottom 23 of the receptacle is sloped at substantially the same angle as screen 7 and is spaced below said screen. The top of the receptacle is spaced below the top of screen means 6 and clear of frames 15, thereby, enabling said receptacle to be reciprocated up and down relative to fixed screen means 6.

Inlet 9 comprises a chute 24 that discharges into a trough extension 25 provided on the upper end of receptacle 8 and it will be evident that a How of liquid-home mica Hakes enters space 21 and falls onto sloping bottom 23.

At the opposite end of the receptacle and from the lowermost point thereof, outlet 10 extends downwardly. The same receives and passes How that traverses the entire extent of sloping bottom 23. Said outlet comprises a Hexible conduit 26 connected to a gradually restricted lower extension 27 of the receptacle.

At said opposite end, in substantial register with exit opening 20, the receptacle is provided with an opening 28 and, forward of said opening, there is provided a discharge chute 29 to comprise outlet 11. The space between openings 20 and 28 is bridged by a flexible jumper element 30 so that flow through opening 20 is guided to opening 28 and thence to chute 29. It will be clear that element 3l) allows reciprocation of the receptacle relative to xed screen means 6. Since outlet 11 is above the highest end of screen 7, only liquid and Hakes that pass upwardly through said screen How through said outlet.

The means 12 for reciprocating receptacle 8 is shown as a pair of pitman rods 31 pivotally connected at 32 to each side of tube 22, at their upper ends, and each provided with a strap 33, at its lower end, for engagement with an eccentric 34 on a shaft 35a. Said shaft in bearing brackets 35 on base le is driven by an electric motor 36 and a suitable connecting drive 37 between said motor and shaft. It is evident that the means 12 shown will rapidly reciprocate receptacle 3 a distance according to twice the eccentricity of the eccentrics 34.

The guiding means 13 is shown as four upright posts 38 on base 14 and extending through guide brackets 39 aixed to receptacle 8. Cushioning springs 40 around said posts smoothen the reciprocating movement of the receptacle.

In operation:

Upon each upward movement of receptacle 8, the bottom thereof upwardly carries the entire mass of liquid and Hakes in the receptacle and, upon downward movement of the receptacle, the liquid will be restored to the initial low position. During such movement, the thicker inert flakes will move up and down with the liquid and, except that they will move with the How along the slope of said bottom, will have no, or very little, relative movement to the liquid. ln other words, the thick, non-buoyant Hakes retain their relative positions in the liquid and move therewith toward and out through outlet 10.

The mentioned upward bodily displacement of the liquid expresses the liquid and the thinner, less inert, and more buoyant Hakes upward through screen 7. Upon downward movement of the body of liquid, said thinner Cit Hakes remain in their upper floated positions from which they settle downward so slowly that the next upward displacement of the liquid only raises them still further. Thus, the successive pulsations intermittently urge the thin Hakes progressively higher until they reach the surface of the liquid.

Because the bottom 23 is sloped, the upward displacement of the Hakes is also in a direction toward outlet 11, the actual direction of movement of the Hakes being substantially at right angles to the angle of slope of said bottom. it is clear, therefore, that the upper portion of the liquid and the Hakes oating therein, at each upward pulsation, is displaced outwardly through outlet 11.

While screen 7 intercepts unduly large-surfaced Hakes, its primary function is to intercept Hakes that have moved thcrepast against downward movement. insofar as classifying the flakes into thick and thin groups, screen 7 has no function and, even if omitted, the pulsations of bottom 23 would move the thinner Hakes upwardly in the liquid reciprocating in tube 16 for ultimate discharge through outlet 11.

lt is intended that the thicker Hakes passing out through outlet 10 not be wasted but subjected to further splitting. The above-mentioned application discloses how this may be accomplished and how the further split Hakes may be returned to the How entering the classifier at inlet 9. In any case, outlet lll is sufficiently restricted to allow the level in receptacle 8 to build up so that the How is divided between outlets 1t) and 11.

While l have disclosed what I now regard as the preferred form of my invention, the same is, of course, subject to moditication without departing from the spirit and scope of my invention. Therefore, l desire to retain to myself such modifications and variations that may fall under the definitions of the appended claims.

Having thus described my invention, what I claim and desire to obtain by Letters Patent, is:

l. A device for separating the thinner from the thicker Hakes in a How of liquid-borne flakes, said device cornprising a receptacle for receiving said How and having a bottom and an outlet from said bottom, an open-bottomed tubular member within the receptacle and having an outlet above the lower end thereof, and means to reciprocate said receptacle relative to the tubular member to bodily reciprocate the liquid and Hakes therein to intermittently displace the thinner Hakes upwardly in the liquid in the tubular member and outwardly from the outlet of said tubular member, the thicker Hakes flowing outward through the outlet in the bottom of the receptacle.

2. A device according to claim l: a screen across the bottom of said tubular member and through which the thinner Hakes pass during upward displacement of the liquid.

3. A device according to claim l: said receptacle bottom being disposed at a downward angle toward the outlet therein, said bottom and the liquid therein, during reciprocation of the receptacle, displacing the Hakes in the liquid at an upward and forward angle substantially normal to the angle of the bottom.

4. A device according to claim 1: said receptacle bottom being disposed at a downward angle toward the outlet therein, said bottom and the liquid therein, during reciprocation of the receptacle, displacing the Hakes in the liquid at an upward and forward angle substantially normal to the angle of the bottom, and a screen across the bottom of the tubular member and arranged substantially parallel to said sloping bottom to pass Hakes upwardly displaced by said bottom.

5. A classifying device of the character described comprising a fixed support, a bottom-open tube tixedly carried by said support, a receptacle surrounding the tube and provided with an upper inlet and a lower outlet, a common outlet from both the tube and receptacle located opposite the inlet and elevated relative to the lower outlet, and means mounted on the support and connected to the receptacle to reciprocate the latter to reciprocate flake-included liquid entering the receptacle through said inlet, the lighter flakes in the liquid being progressively moved during said reciprocation of the liquid upwardly toward said elevated outlet, and the heavier flakes remaining with the liquid moving toward the lower outlet.

6. A classifier device according to claim 5: said receptacle being provided with a sloping bottom disposed at a downward angle toward the lower outlet and imparting to the lighter flakes a directional movement at an angle toward the elevated outlet.

7. A classifier device according to claim 5: said receptacle being provided with a sloping bottom disposed at a downward angle toward the lower outlet and irnparting to the lighter akes a directional movement at an angle toward the elevated outlet, and a screen across the bottom of the rectangular tube to pass relatively smaller thinner akes and intercept relatively larger thinner akes.

8. A method for separating the thinner from the thicker flakes of a flow of liquid-borne mica flakes that consists in conducting said ow in a forward and downward direction while alternately raising and lowering the same to raise the less inert thinner flakes progressively toward the top of the liquid of the ow, utilizing the raising and lowering of the ow to progress said thinner flakes forwardly while the same rise in the liquid, drawing oi the forward portion of the top of the liquid and the thinner flakes oating therein, and simultaneously drawing off the forward portion of the bottom of the ow and the more inert thicker akes therein.

9. A method according to claim 8: screening the flakes that rise toward the top of the liquid to intercept unduly large-surfaced flakes.

References Cited in the le of this patent UNITED STATES PATENTS 166,252 Bradford Aug. 3, 1875 427,249 Bilharz May 6, 1890 713,436 Hodge Nov. 11, 1902 1,741,869 Mett Dec. 31, 1929 1,910,386 Garrett May 23, 1933 2,163,927 Wright June 27, 1939 2,196,457 Constant ,Apr. 9, 1940 2,222,777 Linke Nov. 26, 1940 2,241,646 Rathjens May 13, 1941 2,358,970 Gray Sept. 26, 1944 2,517,832 Blikstad et al. Aug. 8, 1950 2,570,035 Laughlin Oct. 2, 1951 FOREIGN PATENTS 18,057 Great Britain Aug. 9, 1911 

1. A DEVICE FOR SEPARATING THE THINNER FROM THE THICKER FLAKES IN A LOW OF LIQUID-BORNE FLAKES, SAID DEVICE COMPRISING A RECEPTACLE FOR RECEIVING SAID FLOW AND HAVING A BOTTOM AND AN OUTLET FROM SAID BOTTOM AN OPEN-BOTTOMED TUBULAR MEMBER WITHIN THE RECEPTACLE AND HAVING AN OUTLET ABOVE THE LOWER END THEREOF, AND MEANS TO RECIPROCATE SAID RECEPTACLE RELATIVE TO THE TUBULAR MEMBER TO BODILY RECIPROCATE THE LIQUID AND FLAKES THEREIN TO INTERMITTENTLY DISPLACE THE THINNER FLAKES UPWARDLY IN THE LIQUID IN THE TUBULAR MEMBER AND OUTWARDLY FROM THE OUTLET OF SAID TUBULAR MEMBER, THE THICKER FLAKES FLOWING OUTWARD THROUGH THE OUTLET IN THE BOTTOM OF THE RECEPTACLE. 